Purpose: :
To determine quantitative reliability of the Retinal FunctionImager.

Methods: :
A prospective clinical study was done by including 26 patients(45 eyes) who had various diagnosis of retinal vascular diseases.All patients were imaged with fundus fluorescein angiography(FA) (Topcon TRC-501X FA, Topcon Medical Systems Inc., Paramus,NJ) and Retinal Function Imager (RFI) (Optical Imaging Ltd.,Rehovot, Israel). The FA and oxymetry images were overlaid usingAdobe Photoshop to outline non-perfusion areas on the oxymetryimages. Then we did overlaying the retinal blood flow velocityimages over the outlined oxymetry images. Final images werereviewed and be calculated for the localized average blood flowvelocity (average blood flow) over the interesting areas. Wecompared the data for correlations over the perfusion and non-perfusionareas as well as other areas of interesting pathologies. Thestatistical analysis was done to determine statistically significanceof the correlations.

Results: :
Most common diseases were diabetic retinopathy (15 eyes) andretinal vein occlusion (5 eyes). Rosen et al assumed that redcolor in the oxymetry images represented well oxygen perfusionand blue color represented poor oxygen perfusion as they werewell correlated with non-perfusion areas in the FA. We foundthat the average blood flow in the red color areas of oxymetryimages were significantly higher than those of the blue colorareas (p-value < 0.01). We followed up a patient with CRVOfor 6 weeks. The VA had been improving during the follow upperiod. The non-perfusion areas demonstrated by the FA and oxymetrywere improving and well correlated with the changes of the averageblood flow. In a case of sickle cell retinopathy with sea-fanvascular loops, oxymetry revealed the sea-fan lesion in brightred color contrasted with the blue background tissue. Averageblood flow analysis confirmed that the lesion had striking higherblood flow velocity than the non-perfusion background tissue.

Conclusions: :
Retinal Function Imager is another useful and non-invasive device(no dye injection) for demonstration of oxymetry and retinalblood flow velocity in various retinal diseases. Our study revealsthat RFI is reliable in term of quantitative reliability.